Trifolium amoenum |
Trifolium lappaceum |
|
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showy Indian clover, two-fork clover |
burdock clover |
|
Habit | Herbs annual, 45–65 cm, canescent. | Herbs annual, 5–60 cm, hirsute or glabrous. |
Stems | erect, branched from base and distally, or unbranched. |
erect to decumbent, branched. |
Leaves | palmate; stipules ovate-oblong, 0.5–1.8 cm, margins entire, toothed, or irregularly lobed, apex acuminate; petiole 0.5–10 cm; petiolules to 1 mm; leaflets 3, blades broadly obovate or elliptic, 1.7–3.3 × 1.1–2 cm, base cuneate, veins fine, margins entire or denticulate, apex rounded, obtuse, or retuse, surfaces pilose, abaxial less so. |
palmate; stipules oblong, 0.5–1.9 cm, margins entire, apex lanceolate-subulate; petiole 0.3–5 cm; petiolules 1 mm; leaflets 3, blades ovate to obovate, 0.5–1.5 × 0.3–2 cm, base cuneate, veins fine, margins denticulate to dentate, apex rounded, truncate, or emarginate, surfaces hirsute. |
Inflorescences | terminal or axillary, 30–50-flowered, bluntly conic, ellipsoid, globose, or subglobose, 1.5–3 × 1.5–2.5 cm; involucres absent. |
terminal, 40–60-flowered, globose or ovoid, burlike, not disarticulating at maturity, 1–1.4 × 1.8–2 cm; involucres absent. |
Peduncles | 5–15 cm. |
0.1–0.7 cm. |
Pedicels | absent; bracteoles cuplike, to 0.5 mm. |
straight, 0.5 mm; bracteoles absent. |
Flowers | 13–16 mm; calyx tubular, 9–12 mm, pubescent, veins 20–30, tube 3 mm, lobes nearly equal, appearing rigidly erect, linear-setaceous, plumose, sinuses acute, orifice open; corolla white to pink with purple tips, 12–16 mm, banner ovate-oblong, 12–15 × 4 mm, apex broadly rounded, emarginate. |
7–9 mm; calyx campanulate, 7–9 mm, glabrous, veins 20, tube 3 mm, lobes equal, longer than tube, setaceous becoming spinose, orifice hairy, open; corolla pinkish white, 6–10 mm, banner elliptic, 6–9 × 1.5–2 mm, apex emarginate. |
Legumes | obovoid, 4 mm. |
ovoid, leathery distally, transversely dehiscent, 1.5 mm, long-beaked. |
Seeds | 1, dark brown, ellipsoid, 2–3 mm, smooth. |
1, light brown, reddish, or yellow with reddish spots, ovoid, 1 mm, smooth, shiny. |
2n | = 16. |
|
Trifolium amoenum |
Trifolium lappaceum |
|
Phenology | Flowering Apr–May. | Flowering Mar–Jun. |
Habitat | Grassy slopes, swales, clay soils. | Fields, roadsides, grassy areas. |
Elevation | 0–100 m. (0–300 ft.) | 0–300 m. (0–1000 ft.) |
Distribution |
CA
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AL; FL; LA; MS; NC; NJ; PA; SC; TN; TX; s Europe; w Asia; n Africa; Atlantic Islands (Canary Islands) [Introduced in North America; introduced also in s South America (Uruguay), s Africa, Australia]
|
Discussion | Trifolium amoenum was considered extinct (J. P. Smith Jr. 1984) but was rediscovered in 1993 (P. G. Connors 1994). Specimens of T. amoenum are known from Marin, Napa, San Mateo, Solano, and Sonoma counties; it appears to be extant in only single populations in each of Marin and Solano counties. Allozyme studies of the two known populations revealed fixed genetic differences between them (E. E. Knapp and Connors 1999). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Trifolium lappaceum was introduced to the United States about 1903; it has been used as a winter annual pasture and hay crop (E. A. Hollowell 1939), as well as in roadside grass plantings as a nitrogen source. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 11. | FNA vol. 11. |
Parent taxa | ||
Sibling taxa | ||
Name authority | Greene: Fl. Francisc., 27. (1891) | Linnaeus: Sp. Pl. 2: 768. (1753) |
Web links |